mute-first-observable.ts

public muteFirst = <T,R>(first$: Observable<T>, second$: Observable<R>) => Observable.combineLatest(
  first$,
  second$,
  (a,b) => b
).distinctUntilChanged();

muteFirst is a helper that joins two levels of dependency together: From the server to the store via first$, and from the store to the component via second$.

If you have something that is triggered by second$ changing, that distinctUntilChanged can be vital. Else, that event will be triggered when first$ emits also.

If you don't want distinctUntilChanged on b but also don't want updates when a changes, I think this is an alternative:

public muteFirst = <T,R>(first$: Observable<T>, second$: Observable<R>) => second$.withLatestFrom(
  first$,
  (b, a) => b
);